ABSTRACT
Every one knows the external appearance of the cortical substance of the brain. The nerve-fibres which represent the bonds of union between the cortical substance and the central regions of the brain emerge from the midst of the plexus of cells. In the adult, in vertical or horizontal sections of the brain, it is evident that the line of the summits of the convolutions is continuous, that the culminating points are all on the same level; there is some uniformity in the distribution of the activity of nutrition over the whole mass. The capillaries similarly play a very important part in the structure of the cortical layer. Imagine a number of small pyramidal bodies, disposed in series, parallel to one another, united to one another by means of an intermediary network, and moreover regularly stratified, and thus forming layers successively piled up, like the strata of the terrestrial cortex.
